Stress relief of single crystal superalloy articles

Abstract From the Canadian patent

Stress Relief of Single Crystal Superalloy Articles A coated nickel base superalloy single crystal turbine airfoil blade (1), which is subject to gas turbine engine operation, can crack during refurbishment by a stress corrosion mechanism when exposed to certain corrosive media. The rapid thermal cycling that occurs during typical gas turbine engine operation results in high, non-uniform stresses across the airfoil, producing large localized residual strains in the article at ambient temperatures. Exposure to a corrosive environment such as during, coating removal or agressive cleaning can produce, chordwise cracks in a large number of the airfoils exposed. Such cracking is avoided by …